/**
 *Storage封装
 **/

const STORAGE_KEY='mall';
export default {
    //设置存储值
    setItem(key, value,module_name) {
        if (module_name) {
            let val = this.getItem(module_name);
            val[key]=value;
            this.setItem(module_name,val)
        }else {
            let val = this.getStorage();
            val[key]=value
            window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
        }

    },
    //获取某个模块下面的属性下user下面的userName
    getItem(key,module_name){
        if (module_name) {
            let val = this.getItem(module_name);
            if (val) return val[key];
        }
        return this.getStorage()[key];
    },
    getStorage(){
        return JSON.parse(window.sessionStorage.getItem(STORAGE_KEY) || '{}');
    },
    //删除本地存储,如果存在模块模块
    clear(key,module_name){
        let val = this.getStorage();
        if (module_name) {
            if (!val[module_name]) return;
            delete val[module_name][key];
        }else {
            delete val[key];
        }
        //重新写入缓存
        window.sessionStorage.setItem(STORAGE_KEY,JSON.stringify(val));
    }
}